KUNZLI, STEPHANIE L.* and JACK BROWN. Dept. of PSES, University of Idaho, Moscow, Idaho, 83844-2339. - Gene flow between herbicide resistant canola (Brassica napus L.) and a related weed species in the Pacific Northwest.
During the last decade, canola (Brassica napus L.) has become
increasingly popular with growers in the Pacific Northwest.
Problematic weeds have spurred commercial companies to developed
genetically modified herbicide resistant canola cultivars by using
both conventional breeding and recombinant DNA techniques. Among the
concerns related to the use herbicide resistant canola is the
potential transfer of resistance genes to other canola crops and to
closely related weed species. This study investigates potential risks
associated with herbicide resistant canola by first examining gene
transfer between canola and field mustard (B. rapa L., a
closely related weed species) and then determining the viability of
these hybrids. One aim of this study is to examine the possibility of
producing a canola-weed hybrid with multiple herbicide resistance.
Canola lines resistant to one of two different herbicides—Roundup
(Glyphosate) or Raptor (Imazemox)—and seed from a local population of
field mustard were planted in adjacent plots in a field trial. At
maturity, seed from the field mustard plots was harvested by hand
threshing, and planted in seedling-flats in the greenhouse. Plants
possessing 4-6 leaves were then treated with either Roundup or Raptor,
corresponding to the resistant canola the field mustard was adjacent
to in the field. Survivors (putative hybrids) were transplanted into
15 cm pots and sprayed once more to confirm resistance. A total of
3.0% of the hybrids screened showed resistance to Roundup, 6.0% of the
hybrids showed resistance to Raptor. Only 17% of the hybrids were
self-compatible, yet all hybrids indicate some degree of cross
compatibility with other hybrids, suggesting that multiple herbicide
resistant hybrids would be a possibility. A second year of field work
is currently underway to examine the likelihood of cross-pollination
between putative weed-canola hybrids and herbicide resistant canola
that could result in hybrids carrying genes for resistance to two
herbicides.
Key words: Brassica, GMO's, herbicide resistance, pollen transfer, putative hybrids, recombinant DNA